Plug valves generally include a body with a cylindrical or conical inner surface and a rotatable closure member having a complementary sealing surface to block one or more flow passageways extending through the valve. The closure member generally fits very tightly against the internal surface of the body around the flow passage and, particularly when it remains in one position for an extended period of time, it tends to become bound and is turned only with a great deal of effort and difficulty. Others have attempted to lubricate the valve, particularly around the journals, but grease applied to the sealing surface of the valve body or plug tends to become easily dissipated and rubbed away.